…"hell is other people" has always been misunderstood. It has been thought that what I meant by that was that our relations with other people are always poisoned, that they are invariably hellish relations. But what I really mean is something totally different. I mean that if relations with someone else are twisted, vitiated, then that other person can only be hell. Why? Because…when we think about ourselves, when we try to know ourselves, … we use the knowledge of us which other people already have. We judge ourselves with the means other people have and have given us for judging ourselves. Into whatever I say about myself someone else’s judgment always enters. Into whatever I feel within myself someone else’s judgment enters. … But that does not at all mean that one cannot have relations with other people. It simply brings out the capital importance of all other people for each one of us.1Yet another instance in which what a philosopher said is better than what he meant.
1 As quoted at http://rickontheater.blogspot.com/2010/07/most-famous-thing-jean-paul-sartre.html